Andrew Mitchell, the international development secretary, has agreed to honour just eight of a long list of promises made to countries. Photograph: Facundo Arrizabalaga/EPA

A pledge to support free healthcare in the world's poorest countries is one of more than 90 aid commitments to be scrapped by the government.

An email leaked to the Observer reveals that Andrew Mitchell, the international development secretary, has agreed to honour just eight of a long list of promises made to countries.

NGOs have reacted with fury to the news, which suggests an end to government plans to double support for global education; to push for an international treaty regulating the arms trade; and to support water programmes in five countries. It also means no further commitment to a Paris declaration on aid effectiveness.

Joseph O'Reilly, chairman of the UK-based Global Campaign for Education, said plans to scrap education pledges were of huge concern:

"If Andrew Mitchell, who has been a big champion of education, makes this decision it will fatally undermine any chance of getting 72 million children currently out of school into a classroom."

Kirsty Hughes, the head of public policy at Oxfam, said that any move to quietly drop such commitments would be a "desperately backward step for poor people".

The revelations come just weeks after Mitchell said that he wanted to refocus aid efforts towards Afghanistan.

The email follows another leak late last week to the blog Left Foot Forward. It revealed a submission to Mitchell from Nick Dyer, the director of policy at the Department for International Development (DfID). In it he recommended that the minister should honour 19 commitments and drop more than 80. It listed those to be dropped under five headings ranging from "strong public backing" to "unlikely to be noticed". Critics reacted angrily to a line in the submission stating: "We do not recommend any proactive external communications."

The email seen by the Observer suggests that, after reading this proposal, Mitchell decided to go further – cutting by more than half the number of commitments he had been advised to honour. Gareth Thomas, the shadow minister for international development, said: "It is astonishing that Andrew Mitchell seems to want to cut our commitments to aid effectiveness. To not help people to access the best health services in the world is a further sign that he is not going to show international leadership on development."

A spokeswoman for DfID said: "As the secretary of state has made clear, all DfID programmes are currently under review to make sure they have the greatest impact on global poverty… We don't comment on leaked documents."